Patent US4170823A successfully refreshed from Google Patents.
US4170823A
Expired / Lapsed
US
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Fluorescent artificial teeth
Assignee: Dentsply Sirona Inc
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Filing: 1978-02-13
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Granted: 1979-10-16
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Expires: 1998-02-13
Abstract
Abstract An artificial porcelain tooth product containing a combination of terbium and cerium salts to produce a desired fluorescence.
Inventors
- 👤 Milagros B. Smyth
- 👤 James Lee-You
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 12:42
CPC Classifications
A; A61; A61K; A61K6/00; A61K6/15; A61K6/16; A61K6/70; A61K6/78; A61K6/80; A61K6/802; A61K6/822
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
91 words
An artificial porcelain tooth product containing from 0.05 percent to 2.5 percent by weight of terbium oxide and from 0.01 percent to 1.0 percent by weight of cerium oxide and provided that when the cerium oxide is from 0.01 percent to 0.04 percent by weight, the terbium oxide is at least 0.1 percent by weight and when the terbium oxide is from 0.05 to 0.1 percent by weight, the cerium oxide is at least 0.04 percent by weight whereby said tooth product has fluorescent properties comparable to those of natural teeth.
Claim 2
Dependent Claim
91 words
An artificial porcelain tooth product containing from 0.05 percent to 2.5 percent by weight of terbium oxide and from 0.01 percent to 1.0 percent by weight of cerium oxide and provided that when the cerium oxide is from 0.01 percent to 0.04 percent by weight, the terbium oxide is at least 0.1 percent by weight and when the terbium oxide is from 0.05 to 0.1 percent by weight, the cerium oxide is at least 0.04 percent by weight whereby said tooth product has fluorescent properties comparable to those of natural teeth.
Claim 3
Dependent Claim
26 words
An artificial tooth in accordance with claim 1 containing from 0.15 to 1.8 percent of terbium oxide and from 0.02 to 0.5 percent of cerium oxide.
Claim 4
Dependent Claim
25 words
An artificial tooth according to claim 1 containing from 0.5 to 1.2 percent of terbium oxide and from 0.04 to 0.08 percent of cerium oxide.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-10-15 | 1983-04-16 | 1983-10-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-10-15 | 1987-04-16 | 1987-10-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-10-15 | 1991-04-16 | 1991-10-16 | $7700.00 | Window Closed / Lapsed |